相关论文: Vibrational dichroism of chiral valley phonons
At the 2D limit, hexagonal systems such as monolayer transition metal dichalcogenides (TMDs) and graphene exhibit unique coupled spin and momentum-valley physics (valley pseudospin) owing to broken spatial inversion symmetry and strong…
By enabling control of valley degrees of freedom in transition-metal dichalcogenides, valley-selective circular dichroism has become a key concept in valleytronics. In this manuscript, we show that valley excitons -- bound electron-hole…
In monolayer hexagonal lattices, two inequivalent valleys appear in the Brillouin zone. With inversion symmetry breaking, we find chiral phonons with valley contrasting circular polarization and ionic magnetic moment. At valley centers,…
We report a theoretical investigation of the ultrafast dynamics of electrons and phonons in strained monolayer WS$_2$ following photoexcitation. We show that strain substantially modifies the phase space for electron-phonon scattering,…
Although single-layer transition-metal dichalcogenides with novel valley functionalities are promising candidate to realize valleytronic devices, the essential understanding of valley depolarization mechanisms is still incomplete. Based on…
In transition metal dichalcogenides, the valley degree of freedom directly couples valley-polarised excitons - excited by circularly polarised light - to valley-dependent chiral photons, enabling ultrafast light-driven valleytronics.…
We observe a set of three replica luminescent peaks at ~21.4 meV below the dark exciton, negative and positive dark trions (or exciton-polarons) in monolayer WSe2. The replica redshift energy matches the energy of the zone-center E"-mode…
Lattice vibrations carrying angular momentum, known as chiral phonons, have emerged as a promising route to control and understand complex material properties, yet their deterministic manipulation remains largely unexplored. Here we…
Valley, as a degree of freedom, has been exploited to realize valley-selective Hall transport and circular dichroism in two-dimensional layered materials. On the other hand, orbital angular momentum of light with helical phase distribution…
Valleytronics targets the exploitation of the additional degrees of freedom in materials where the energy of the carriers may assume several equal minimum values (valleys) at non-equivalent points of the reciprocal space. In single layers…
We show that excitons and free carriers in K and K' valleys of transition metal dichalcogenide monolayers can be entangled with respect to their valley degree of freedom by absorbing linearly polarized single photons. This effect does not…
Optical interband transitions in monolayer transition metal dichalcogenides such as WSe2 and MoS2 are governed by chiral selection rules. This allows efficient optical initialization of an electron in a specific K-valley in momentum space.…
Chiral phonons possessing valley pseudo angular momentum (PAM) underlie a diversity of quantum phenomena of fundamental and applied importance, but are challenging to probe directly. We show that deficiencies of typical momentum-resolved…
Chirality, the breaking of improper rotational symmetry, is a fundamental concept spanning diverse scientific domains. In condensed matter physics, chiral phonons, originating from circular atomic motions that carry angular momentum, have…
We investigate the electric response of chiral phonons on the low-buckled group-IVA monolayers by performing first-principles calculations. The vertical electric field breaks the degeneracy of phonon modes at high-symmetry $\pm K$ points of…
In single-layer WSe$_2$, a paradigmatic semiconducting transition metal dichalcogenide, a circularly polarized laser field can selectively excite electronic transitions in one of the inequivalent $K^{\pm}$ valleys. Such selective valley…
Optical properties of semiconducting monolayer transition metal dichalcogenides have received a lot of attention in recent years, following the discovery of the valley selective optical population of either $K_{+}$ or $ K_{-}$ valleys at…
The illumination of a single-layer transition metal dichalcogenide with an elliptically-polarized light beam is shown to give rise to a differential rate of inter-band carrier excitation between the valence and conduction states around the…
Chiral phonons, quantized lattice vibrations with circular polarization and non-zero angular momentum, offer new perspectives for phononic and quantum device engineering. Graphyne could be a promising candidate due to its unique lattice…
Electrons in two-dimensional materials possess an additional quantum attribute, the valley pseudospin, labelled as $\mathbf{K}$ and $\mathbf{K}^{\prime}$ -- analogous to the spin up and spin down. The majority of research to achieve…